A nut, flat on top and bottom having 6 flat sides. For items which have internal tapered or straight (parallel) pipe threads, specific electrical conduit size designation, and which when installed, provide a method of tightening to lock the connection, see LOCKNUT, ELECTRICAL CONDUIT. See also LOCKNUT, TUBE FITTING. For items having a thickness (or height) exceeding two times the width across the flats, use POST, ELECTRICAL-MECHANICAL EQUIPMENT. (When height or thickness and/or width across the flats is designated as a tolerance dimension, the maximum dimension will be used to determine compliance.)